Methods for manufacturing polycrystalline ultra-hard constructions and polycrystalline ultra-hard constructions

ABSTRACT

Polycrystalline ultra-hard constructions are made by subjecting a sintered ultra-hard body, substantially free of a sintering catalyst material, to a further HPHT process. The process is controlled to initially melt and infiltrating a filler material into the sintered ultra-hard body to form a filler region having interstitial regions filled with the filler material. The filler region extends a partial depth into the sintered ultra-hard body and is formed at a temperature below the melting temperature of an infiltrant material. Next, the process is controlled to melt and infiltrate the infiltrant material into the sintered ultra-hard body to form an infiltrant region that extends a partial depth into the sintered ultra-hard body. A portion of the filler region and/or the infiltrant region may be removed to form a thermally stable region.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/578,079 filed Dec. 20, 2011, which isincorporated herein by reference in its entirety.

FIELD

Improved methods for forming polycrystalline ultra-hard constructions,and polycrystalline ultra-hard constructions resulting from suchimproved methods, are disclosed herein.

BACKGROUND

The existence and use polycrystalline diamond material types for formingtooling, cutting and/or wear elements is well known in the art. Forexample, polycrystalline diamond (PCD) is known to be used as cuttingelements to remove metals, rock, plastic and a variety of compositematerials. Such known polycrystalline diamond materials have amicrostructure characterized by a polycrystalline diamond matrix firstphase, that generally occupies the highest volume percent in themicrostructure and that has the greatest hardness, and a plurality ofsecond phases, that are generally filled with a solvent catalystmaterial used to facilitate the bonding together of diamond particles,grains or crystals together to form the polycrystalline matrix firstphase during sintering.

PCD known in the art is formed by combining diamond grains (that willcreate the polycrystalline matrix first phase) with a suitable solventcatalyst material (that will create the second phase) to form a mixture.The solvent catalyst material can be provided in the form of powder andmixed with the diamond grains or can be infiltrated into the diamondgrains during high pressure/high temperature (HPHT) sintering. Thediamond grains and solvent catalyst material are sintered at extremelyhigh pressure/high temperature process conditions, during which time thesolvent catalyst material promotes desired intercrystallinediamond-to-diamond bonding between the grains, thereby forming a PCDstructure.

Solvent catalyst materials used for forming conventional PCD includesolvent metals from Group VIII of the Periodic table, with cobalt (Co)being the most common. Conventional PCD can comprise from about 85 to95% by volume diamond and a remaining amount being the solvent metalcatalyst material. The solvent catalyst material is present in themicrostructure of the PCD material within interstices or interstitialregions that exist between the directly bonded together diamondparticles and/or along the surfaces of the diamond particles.

The resulting PCD structure produces enhanced properties of wearresistance and hardness, making PCD materials extremely useful inaggressive wear and cutting applications where high levels of wearresistance and hardness are desired. Industries that utilize such PCDmaterials for cutting, e.g., in the form of a cutting element, includeautomotive, oil and gas, aerospace, nuclear and transportation tomention only a few.

For use in the oil production industry, such PCD cutting elements areprovided in the form of specially designed cutting elements such asshear cutters that are configured for attachment with a subterraneandrilling device, e.g., a shear or drag bit. Thus, such PCD shear cuttersare used as the cutting elements in shear bits that drill holes in theearth for oil and gas exploration. Such shear cutters generally comprisea PCD body that is joined to substrate, e.g., a substrate that is formedfrom cemented tungsten carbide. The shear cutter is manufactured usingan HPHT process that utilizes cobalt as a catalytic second phasematerial that facilitates liquid-phase sintering between diamondparticles to form a single interconnected polycrystalline matrix ofdiamond with cobalt dispersed throughout the matrix.

The shear cutter is attached to the shear bit via the substrate, usuallyby a braze material, leaving the PCD body exposed as a cutting elementto shear rock as the shear bit rotates. High forces are generated at thePCD/rock interface to shear the rock away. In addition, hightemperatures are generated at this cutting interface, which shorten thecutting life of the PCD cutting edge. High temperatures incurred duringoperation cause the cobalt in the diamond matrix to thermally expand andeven change phase, which thermal expansion is known to cause the diamondcrystalline bonds within the microstructure to be broken at or near thecutting edge thereby also operating to reduce the life of the PCDcutter. Also, in high temperature oxidizing cutting environments, thecobalt in the PCD matrix will facilitate the conversion of diamond backto graphite, which is also known to radically decrease the performancelife of the cutting element.

Attempts in the art to address the above-noted limitations have largelyfocused on the solvent catalyst material's degradation of the PCDconstruction by catalytic operation, and have involved removing thecatalyst material from the PCD construction for the purpose of enhancingthe service life of PCD cutting elements. For example, it is known totreat the PCD body to remove the solvent catalyst material therefrom,which treatment has been shown to produce a resulting diamond bodyhaving enhanced cutting performance. One known way of doing thisinvolves at least a two-stage technique of first forming a conventionalsintered PCD body, by combining diamond grains and a solvent catalystmaterial and subjecting the same to HPHT process as described above, andthen removing the solvent catalyst material therefrom, e.g., by acidleaching process.

As discussed in US 2008/0230280 A1 and US 2008/0223623 A1, an approachto providing a thermally stable PCD construction is to form a PCD bodyduring a HPHT sintering process and then remove substantially all of thesolvent catalyst material from the PCD body so that the remainingthermally stable PCD (TSP) body comprises essentially a matrix ofintercrystalline bonded together diamond crystals with no other materialoccupying the interstitial regions between the diamond crystals. Whilesuch a TSP body may display improved thermal properties, it now lackstoughness that may make it unsuited for particular high-impact cuttingand/or wear applications.

Therefore, it is known to infiltrate the TSP with an infiltrantmaterial, for example selected from Group VIII elements from thePeriodic Table, such as Co, Ni and/or Fe. The infiltrant material may beprovided via migration by re-bonding the treated PCD body to a substrateduring a HPHT re-bonding process, wherein the infiltrant materialpresent as a constituent in the substrate liquefies and infiltrates intothe TSP body, also attaching the body to the substrate. Afterinfiltration of the infiltrant material, the infiltrated TSP body istreated again, this time, to remove the infiltrant material from asurface of the PCD body.

Such reattached treated PCD (or TSP) cutting elements comprising suchinfiltrants can fail prematurely during use. Without wishing to be boundby any particular theory, it is believed that the failure of suchreattached PCD cutting elements can be due to insufficient migration ofthe infiltrant material into the treated PCD body during theinfiltration process (e.g., re-bonding process). Insufficient migrationof the infiltrant material produces residual porosity in the infiltratedTSP body. If the pores or voids created from treating the PCD body toremove the catalyst material are partially infiltrated, or otherwise notproperly infiltrated during the infiltration process, the empty porescan weaken the body and create structural flaws in the microstructureleading to premature failure of the cutting element. Partialinfiltration, thus makes the PCD body vulnerable to cracking duringfinishing operations such as lapping or grinding, and also can makere-treating the PCD body to remove infiltrant material more difficult,which can weaken the bond between the PCD body and an attachedsubstrate.

Insufficient migration of the infiltrant during the infiltration processcan be due to the sluggish infiltration kinetics of the infiltrantmaterial (e.g., cobalt) and the porosity and/or the small pores of thePCD body. For example, the infiltration of an infiltrant such as cobaltfrom carbide, e.g., present as a constituent in a WC—Co substrate, isvery difficult such that in many cases the cobalt is not able to fullyinfiltrate the PCD body during HPHT processing, leading to thedegradation of diamond in the partially infiltrated region, andoperating to reduce the wear resistance of the PCD body.

Further, when the treated PCD body is taken to pressure and heated tomelt the infiltrant (e.g., cobalt), there is a period of time which thediamond in the pore space of the body is out of the diamond stableregion, i.e., there is temperature but insufficient pressure. Thissituation can cause damage to the diamond structure and weaken thediamond bonds, operating to further reduce the wear resistance, strengthand service life of the PCD body and cutting element formed therefrom.

As discussed in US 2010/0320006 A1, one approach to improving theinfiltration of the infiltrant material is to increase the porosity inthe treated PCD body near the source of the infiltrant material (e.g.,substrate). While such approach may operate to facilitate the migrationof the infiltrant into the PCD body, the increase in porosity decreasesthe overall diamond density or diamond volume of the PCD body, therebyoperating to weaken the structure of the PCD body and reduce the servicelife of the cutting element formed therefrom.

It is, therefore, desirable to provide polycrystalline ultra-hardconstructions, and methods for making the same, engineered in a mannerthat not only have improved thermal characteristics to provide animproved degree of thermal stability during use, but that do so in amanner that maintains the desired wear resistance and diamond density ordiamond volume, thereby minimizing or eliminating known mechanisms ofpremature failure as compared to conventional PCD constructions. It isfurther desired that such polycrystalline ultra-hard constructions beengineered in a manner that facilitates the manufacturing process, toprovide manufacturing efficiencies when compared to conventional PCDconstructions.

SUMMARY

Polycrystalline ultra-hard constructions prepared according toprinciples of this disclosure are made by subjecting a sinteredultra-hard body that is substantially free of a catalyst material usedto initially sinter the ultra-hard body at high pressure/hightemperature conditions to a further high pressure/high temperatureprocess to introduce an infiltrant material. The sintered ultra-hardbody comprises a matrix phase of directly bonded together ultra-hardparticles, and a plurality of substantially empty interstitial regionsdisposed within the matrix. In an example embodiment, the ultra-hardmaterial is diamond, and the matrix phase is intercrystalline bondedtogether diamond crystals.

In an example embodiment, the further high pressure/high temperatureprocess is performed in a controlled manner to minimize damage to thematrix phase. In such example embodiment, the process comprises meltingand infiltrating a filler material into the sintered ultra-hard body toform a filler region having interstitial regions filled with the fillermaterial. In an example embodiment, the filler region extends a partialdepth into the sintered ultra-hard body and is formed at a temperaturebelow the melting temperature of an infiltrant material and at apressure below about 3 GPa. The filler material may be placed adjacent asurface, e.g., a working surface, of the ultra-hard body before meltingand introducing the filler material.

In an example embodiment, the filler material has a melting temperatureof less than about 1,000° C., may have a melting temperature of lessthan about 700° C., and in some embodiments may have a meltingtemperature of less than about 300° C. The filler material may beselected from the group including aluminum, gallium, copper, zinc,silver, indium, thallium, tin, lead, bismuth, alloys, metal salts,carbonates, fluorides, chlorides, bromides, sulfides and mixturesthereof. In an example embodiment, the filler material may be an alloywhich is a eutectic alloy.

The process further comprises next melting and infiltrating theinfiltrant material into the sintered ultra-hard body, now comprisingthe filler region, to form an infiltrant region. In an exampleembodiment, the melting and infiltrating of the infiltrant materialoccurs at a temperature and pressure greater than that used to form thefiller region. The infiltrant region extends a partial depth into thesintered ultra-hard body. Thus, after melting and infiltrating theinfiltrant material, the sintered ultra-hard body consists of the fillerregion and infiltrant region.

In an example embodiment, during melting and infiltrating the infiltrantmaterial, a sufficient population of the interstitial regions within thesintered ultra-hard body is filled with either the filler material orthe infiltrant material to ensure that the sintered ultra-hard bodyremains above the Berman/Simon diamond-graphite equilibrium line. Forexample, after melting and infiltrating the infiltrant material lessthan about 2 percent of the population of the interstitial regionswithin the sintered ultra-hard body are empty, preferably about 0 to 2percent of the population of the interstitial regions within thesintered ultra-hard body are empty, and more preferably about 0 to 1percent of the population of the interstitial regions within thesintered ultra-hard body are empty. In an example, after melting andinfiltrating the infiltrant material essentially 100 percent of theinterstitial regions are filled.

During the further high pressure/high temperature process, a substratemay be attached to the ultra-hard body, e.g., the substrate may be thesource of the infiltrant, and may be attached to the attached to thebody adjacent the body infiltrant region.

In an example embodiment, after the infiltrant region is formed, theultra-hard body may be treated to remove all or a portion of the fillermaterial from the filler region to provide a thermally stable region.The thermally stable region may comprise less than about 12 percent byweight filler material, based on the total weight of the ultra-hardbody, and in some embodiments the thermally stable region may compriseless than about 2 percent by weight filler material, based on the totalweight of the ultra-hard body. In an example embodiment, the thermallystable region extends a depth of at least about 0.5 mm from a surface ofthe ultra-hard body including one or both of a top and side surface.Additionally, the thermally stable region may include a portion of theinfiltrant region.

Polycrystalline ultra-hard constructions made in this manner displayimproved thermal characteristics to provide an improved degree ofthermal stability during use, when compared to conventionalpolycrystalline ultra-hard constructions, and do so in a manner thatmaintains the desired wear resistance and diamond density or diamondvolume, thus minimizing or eliminating known mechanisms of prematurefailure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of polycrystalline ultra-hardconstructions and methods of making the same as disclosed herein will beappreciated as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings wherein:

FIG. 1 illustrates a phase diagram for diamond;

FIG. 2 illustrates a cross-sectional schematic side view of anultra-hard construction according to one or more embodiments of thepresent disclosure;

FIG. 3 illustrates a cross-sectional schematic side view of anultra-hard construction according to one or more embodiments of thepresent disclosure;

FIG. 4A is a schematic view of a region taken from a polycrystallinediamond body comprising an infiltrant material disposed interstitiallybetween bonded together diamond particles according to methods disclosedherein;

FIG. 4B is a schematic view of a region taken from a polycrystallinediamond body that is substantially free of the infiltrant material ofFIG. 4A according to methods disclosed herein;

FIGS. 5A to 5C are cross-sectional schematic side views ofpolycrystalline diamond constructions of one or more embodiments of thepresent disclosure during different stages of formation;

FIGS. 6A to 6C are cross-sectional schematic side views ofpolycrystalline diamond constructions of one or more embodiments of thepresent disclosure during different stages of formation;

FIG. 7 is a perspective side view of an insert comprising apolycrystalline diamond construction as disclosed herein;

FIG. 8 is a perspective side view of a roller cone drill bit comprisinga number of the inserts of FIG. 7;

FIG. 9 is a perspective side view of a percussion or hammer bitcomprising a number of inserts of FIG. 7;

FIG. 10 is a schematic perspective side view of a diamond shear cuttercomprising a polycrystalline diamond construction as disclosed herein;and

FIG. 11 is a perspective side view of a drag bit comprising a number ofthe shear cutters of FIG. 10.

DETAILED DESCRIPTION

Ultra-hard constructions of the present disclosure, for examplepolycrystalline diamond constructions, have a material microstructurecomprising a polycrystalline matrix first phase that is formed frombonded together ultra-hard particles, such as directly bonded togetherdiamond particles (grains or crystals), i.e., intercrystalline diamond.The ultra-hard body further includes interstitial regions disposedbetween the ultra-hard particles. The interstitial regions initiallycontain the catalyst material utilized to form the ultra-hard bodyduring HPHT processing. The ultra-hard body is treated to remove thecatalyst material from throughout the body. An infiltrant material isthen introduced into at least one region of the treated ultra-hard body,and a filler material is also introduced into at least one other regionof the treated ultra-hard body.

The resulting ultra-hard body comprises at least one region of the bodycontaining a population of interstitial regions filled with aninfiltrant material (infiltrant region), and at least one other regionof the body containing a population of interstitial regions filled witha filler material (filler region). The filler material has a meltingtemperature that is lower than the infiltrant material. In one or moreembodiments, the filler material may be non-reactive or inert to theultra-hard body. In one or more embodiments, at least a portion of theinfiltrant material may be provided from a substrate attached to theultra-hard body during a re-bonding process, thereby forming apolycrystalline ultra-hard compact construction. However,polycrystalline ultra-hard constructions of the present disclosure maybe provided in the form of a polycrystalline ultra-hard body that may ormay not be attached to a substrate.

Use of a lower melting temperature filler material to infiltrate atleast one region of the polycrystalline ultra-hard body provides forimproved infiltration of the ultra-hard body by both the infiltrantmaterial and the filler material. Having un-infiltrated or partiallyinfiltrated interstitial regions present during infiltration of thetreated ultra-hard body creates a region within the ultra-hard material,for example diamond, that is exposed to ultra high temperatures withoutsufficient high pressure, e.g., during HPHT processing.

Lack of adequate filler or infiltrant, e.g., metal or salt, within theinterstitial regions during such HPHT processing results in insufficientpressure being experienced within these regions, which shifts thediamond out of the diamond stable region and into the graphite region ofthe phase diagram as illustrated in FIG. 1. Localized graphitization ofthe diamond weakens the diamond material and ultra-hard body formedtherefrom, which can lead to unsatisfactory performance and reducedservice life when placed into an end-use application. Polycrystallineultra-hard constructions, prepared according to principles of thepresent disclosure are substantially free of interstitial regions thatare un-infiltrated or partially infiltrated through the use of theinfiltrant and filler, thereby producing an ultra-hard body displayingimproved properties of thermal stability, wear resistance, impactresistance and/or toughness when compared known PCD constructions.

In one or more embodiments of the present disclosure, the ultra-hardbody comprising at least one infiltrant region and at least one fillerregion may be further treated to remove the filler material from apopulation of the interstitial regions of the body, thereby forming athermally stable region with interstitial regions that may besubstantially free of the filler material, for example substantiallyempty interstitial regions.

As the interstitial regions (pores) can be very small, especially withina sintered ultra-hard body subjected to an additional HPHT process, theuse of a filler material as described herein allows for betterinfiltration into the ultra-hard body and for more complete pore fillingthan with the use of an infiltration material, e.g., such as oneselected from Group VIII of the Periodic table like Co, Ni and/or Fe,due partially to the lower viscosity of the filler material. Asdiscussed above, the improved infiltration provided by the fillermaterial operates to reduce the amount of ultra-hard material exposed toHPHT conditions outside the stable region due to unfilled pores thatcause the pressure in such region to fall below the diamond stablepressure.

Additionally, using the filler material allows for deeper infiltrationand penetration into the ultra-hard body from a working surface.Additionally, the filler material is more easily removed as compared toconventional infiltrant materials, such as those disclosed above,thereby enabling deeper leach depths to be obtained without theassociated increase in leach time and difficulty. Additionally, use ofthe filler material enables removal by techniques different from and/ormore efficient than those associated with catalyst and infiltrantmaterials. For example, filler materials as disclosed herein may bedrawn out of the ultra-hard body by heat, such as in the case of thefiller material being tin, in which case a copper disc can be placedadjacent the ultra-hard body to melt the tin and draw the tin out of thebody and onto the disc.

As used herein, the term “ultra-hard” is understood to refer generallyto materials having a Vickers hardness of greater than about 4,000,including but not limited to materials such as diamond, cubic boronnitride and the like.

As used herein, the term “working surface” refers to the surface orsurfaces of the ultra-hard body intended to engage the formation duringdrilling. The working surface may include at least a portion of the topsurface, side surface, cutting edge and combinations thereof.

As used herein, the term “depth” refers to the depth within the PCD bodyas measured inwardly perpendicular from the surface of interest of thebody to the targeted interface (i.e., the boundary between regionswithin the PCD body).

As used herein, the term “polycrystalline diamond” refers to a materialthat has been formed at high pressure/high temperature (HPHT) conditionsthat has a material microstructure comprising a matrix phase ofbonded-together diamond particles. The material microstructure furtherincludes a plurality of interstitial regions that are disposed betweenthe diamond particles. A catalyst material occupies the interstitialregions after the diamond powder is subjected to a HPHT sinteringprocess.

As used herein, a plurality of items, structural elements, compositionalelements and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Concentrations, quantities, amounts, and other numerical data may bepresented herein in a range format. It is to be understood that suchrange format is used merely for convenience and brevity and should beinterpreted flexibly to include not only the numerical values explicitlyrecited as the limits of the range, but also to include all theindividual numerical values or sub-ranges encompassed within that rangeas if each numerical value and sub-range is explicitly recited. Forexample, a numerical range of 1 to 4.5 should be interpreted to includenot only the explicitly recited limits of 1 to 4.5, but also includeindividual numerals such as 2, 3, 4 and sub-ranges such as 1 to 3, 2 to4, etc. The same principle applies to ranges reciting only one numericalvalue, such as “at most 4.5,” which should be interpreted to include allof the above-recited values and ranges. Further, such an interpretationshould apply regardless of the breadth of the range or thecharacteristic being described.

Polycrystalline diamond (PCD) useful for making ultra-hard constructionsas disclosed herein may be formed by conventional methods of subjectingprecursor diamond grains or powder to HPHT sintering conditions in thepresence of a catalyst material, e.g., a solvent metal catalyst, thatfunctions to facilitate the direct bonding together of the diamondgrains at temperatures of between about 1,350 to 1,500° C., andpressures of 5,000 MPa or higher. Suitable catalyst materials useful formaking PCD include those metals identified in Group VIII of the Periodictable (CAS version in the CRC Handbook of Chemistry and Physics 75^(th)edition, front cover), such as Co, Ni, Fe and combinations thereof.

As used herein, the term “thermal characteristics” is understood torefer to characteristics that impact the thermal stability of theresulting polycrystalline construction, which can depend on such factorsas the relative thermal compatibilities such as thermal expansionproperties, of the materials occupying and/or forming the differentconstruction material phases.

As used herein, the term “catalyzing material” refers to a material thatmay be used to initially form the ultra-hard material body (e.g.,polycrystalline diamond body).

As used herein, the term “infiltrant material” is understood to refer tomaterials other than the catalyst material that was used to initiallyform or sinter the ultra-hard material body, and may include materialsidentified in Group VIII of the Periodic table that have subsequentlybeen introduced into the sintered ultra-hard material body after thecatalyst material used to initially form the same has been removedtherefrom. Additionally, the term “infiltrant material” is not intendedto be limiting on the particular method or technique used to introducesuch material into the already-formed ultra-hard material body.

In one or more embodiment, the diamond body comprises a first region(infiltrant region) that includes an infiltrant material. The infiltrantmaterial may be a Group VIII material. The infiltrant material isdisposed within a population of the interstitial regions within thefirst region. In an example embodiment, the first region of the diamondbody is positioned remote from a diamond body surface, e.g., a workingsurface. The diamond body includes a second region (filler region) thatextends a depth from the diamond body surface, e.g., a working surface.In one or more embodiments, the second region may be positioned adjacentthe first region. In this embodiment, it is understood that there maynot be a distinct interface between the first and second region butthere may be a zone of intermixing between the infiltrant material andthe filler material along the interface. The major portion of the secondregion comprises interstitial regions that are substantially free of theinfiltrant material and contain the filler material. In an exampleembodiment, the second region extends a depth from one or more surfacesof the body including top, cutting edge and/or side surfaces, which mayor may not be working surfaces.

In the one or more embodiments, where the diamond body is furthertreated to remove the filler material therefrom, the diamond bodycomprises a third region (thermally stable region) that extends a depthfrom the diamond body surface, e.g., a working surface. In one or moreembodiments, the third region may extend a depth into the second region(filler region).

As illustrated in FIG. 2, a PCD body 211 is formed containing a firstregion (infiltrant region) 222 and a second region (filler region) 233,wherein the first region extends a depth from one body surface inwardlytowards the body, and the second region extends a depth from anotherbody surface inwardly towards the body. The PCD body is subsequentlytreated to form a third region (thermally stable region) 244, whereinthe interstitial regions within the third region are substantiallyempty, and wherein the third region extends a depth from the same bodysurface as the second region. In one or more embodiments, the thirdregion 244 may extend a depth through the second region (filler region)and into the first region (infiltrant region). If desired, the thirdregion may be contained to a partial or full depth of the second region,i.e., without extending into the first region.

As illustrated in FIG. 3, a PCD body 311 is formed containing a firstregion (infiltrant region) 322 and a second region (filler region) 333.The PCD body is subsequently treated to form a third region (thermallystable region) 344 extending through the second region (filler region)333 and into a portion of the first region (infiltrant region) 322forming a fourth region of infiltrant material 355. The interfacebetween the first region and the second region is indicated by a dashedline 366. In such embodiment, the interstitial regions disposed withinthe fourth region are substantially empty.

In one or more embodiments, polycrystalline diamond constructions asdisclosed herein may include a substrate that is attached to the diamondbody to form a polycrystalline diamond compact construction. In anexample embodiment, the substrate may be attached to the diamond bodyadjacent the first region. The substrate that is ultimately attached tothe diamond body may provide at least a portion of (for example, a majorportion of) the infiltrant material and may be made from the same ordifferent material as that which may have been used as a source of thecatalyst material during the initial process of forming the diamondbonded matrix phase. Example substrate materials useful for providingthe infiltrant material include those conventionally used to form PCDsuch as cermets, and in an example embodiment cemented tungsten carbide.

FIG. 4A schematically illustrates an infiltrant region 10 of apolycrystalline diamond construction prepared according to one or moreembodiments of the present disclosure that includes the infiltrantmaterial. Specifically, the region 10 includes a material microstructurecomprising a plurality of bonded together diamond particles 12, formingan intercrystalline diamond matrix first phase, and the infiltrantmaterial 14 that is disposed in the plurality of interstitial regionsexisting between the bonded together diamond particles and/or that areattached to the surfaces of the diamond particles. For purposes ofclarity, it is understood that the region 10 of the polycrystallineconstruction is one taken from a PCD body after it has been modified inaccordance with the present disclosure to: 1) remove the catalystmaterial that was used to initially form/sinter the PCD body; and 2)fill a population of the interstitial regions with an infiltrantmaterial. If desired, the region 10 illustrated in FIG. 4A can be thatof a filler region, wherein the material disposed within theinterstitial regions is filler material rather than infiltrant material.

FIG. 4B schematically illustrates a thermally stable region 22 of apolycrystalline diamond construction prepared according to one or moreembodiments of the present disclosure that is substantially free of anyinfiltrant material or filler material. Like the polycrystalline diamondconstruction region illustrated in FIG. 4A, the region 22 includes amaterial microstructure comprising the plurality of bonded togetherdiamond particles 24, forming the intercrystalline diamond matrix firstphase. Unlike the region 10 illustrated in FIG. 4A, this region of thediamond body 22 has been modified to remove any infiltrant material orfiller material from the plurality of interstitial regions and, thuscomprises a plurality of interstitial regions 26 that are substantiallyempty or free of the infiltrant material or the filler material. Again,it is understood that the region 22 of the polycrystalline diamondconstruction is one taken from a diamond body after it has been modifiedin accordance with the present disclosure to: 1) remove the catalystmaterial that was used to initially form the PCD body therefrom; 2)infiltrate the interstitial regions with infiltrant material or fillermaterial; and 3) remove the infiltrant or filler material from theinterstitial regions.

FIGS. 5A, 5B, and 5C each schematically illustrate an example embodimentpolycrystalline diamond construction 30 as disclosed herein at differentstages of formation. FIG. 5A illustrates a first stage of formation,starting with a conventional PCD body 32 in its initial form aftersintering by conventional HPHT sintering process. At this early stage,the PCD body 32 comprises a polycrystalline diamond matrix phase and asolvent catalyst metal material, such as cobalt, used to form thediamond matrix phase and that is disposed within the interstitialregions between the bonded together diamond particles forming the matrixphase. The solvent metal catalyst material may be added to the precursordiamond grains or powder as a raw material powder prior to sintering,may be contained within the diamond grains or powder, or may beinfiltrated into the diamond grains or powder during the sinteringprocess from a substrate containing the solvent metal catalyst materialand that is placed adjacent the diamond powder and exposed to the HPHTsintering conditions. In an example embodiment, the solvent metalcatalyst material is provided from a substrate 34, e.g., a WC—Cosubstrate, during the HPHT sintering process.

Diamond grains useful for forming the PCD body include synthetic ornatural diamond powders having an average diameter grain size in therange of from submicrometer in size to 100 micrometers, and morepreferably in the range of from about 0.5 or sub micron to 80micrometers. The diamond powder may contain grains having a mono ormulti-modal particle size distribution. In the event that diamondpowders are used having differently sized grains, the diamond grains aremixed together by conventional process, such as by ball or attrittormilling or dry mixing methods for as much time as necessary to ensuregood uniform distribution. The PCD body may be formed from a singlediamond powder or may be formed from multiple layers of diamond powderswhich may provide for a gradual or step-wise gradient in one or moreproperties within the sintered PCD body such as diamond density, averagediamond grain size, catalyst material content, which can provide adesired change or level of strength and thermal abrasion properties.

As noted above, the diamond powder may be combined with a desiredsolvent metal catalyst powder to facilitate diamond bonding during theHPHT process and/or the solvent metal catalyst may be provided byinfiltration from a substrate positioned adjacent the diamond powderduring the HPHT process. Suitable solvent metal catalyst materialsuseful for forming the PCD body include those metals selected from GroupVIII elements of the Periodic table. An example solvent metal catalystis cobalt (Co).

The diamond powder mixture can be provided in the form of a green-statepart or mixture comprising diamond powder that is contained by a bindingagent, e.g., in the form of diamond tape or other formable/conformablediamond mixture product to facilitate the manufacturing process. In theevent that the diamond powder is provided in the form of such agreen-state part it is desirable that a preheating process take placebefore HPHT consolidation and sintering to drive off the bindermaterial. In an example embodiment, the PCD body resulting from theabove-described HPHT process may have a diamond volume content in therange of from about 85 to 95 percent. For certain applications, a higherdiamond volume content up to about 98 percent may be desired.

The diamond powder or green-state part is loaded into a desiredcontainer for placement within a suitable HPHT consolidation andsintering device. In an example embodiment, where the source of thesolvent metal catalyst material is provided by infiltration from asubstrate, a suitable substrate material is disposed within theconsolidation and sintering device adjacent the diamond powder mixture.In one or more embodiments, the substrate is provided in a preformedstate. Substrates useful for forming the PCD body can be selected fromthe same general types of materials conventionally used to formsubstrates for conventional PCD materials, including carbides, nitrides,carbonitrides, ceramic materials, metallic materials, cermet materialsand mixtures thereof. A feature of the substrate used for forming thePCD body is that it includes a solvent metal catalyst capable of meltingand infiltrating into the adjacent volume of diamond powder tofacilitate conventional diamond-to-diamond intercrystalline bondingduring HPHT processing to form/sinter the PCD body. An example substratematerial is cemented tungsten carbide (WC—Co).

Where the solvent metal catalyst is provided by infiltration from asubstrate, the container including the diamond particles and thesubstrate is loaded into the HPHT device and the device is thenactivated to subject the container to a desired HPHT condition to effectconsolidation and sintering of the diamond particles. In an exampleembodiment, the device is controlled so that the container is subjectedto a HPHT process having a pressure of 5,000 MPa or more and atemperature of from about 1,350° C. to 1,500° C. for a predeterminedperiod of time. At this pressure and temperature, the solvent metalcatalyst melts and infiltrates into the diamond particles, therebysintering the diamond grains to form conventional PCD.

While a particular pressure and temperature range for this HPHT processhas been provided, it is to be understood that such processingconditions can and will vary depending on such factors as the typeand/or amount of solvent metal catalyst used in the substrate, as wellas the type and/or amount of diamond particles used to form the PCD bodyor region. After the HPHT sintering process is completed, the containeris removed from the HPHT device, and the assembly comprising the bondedtogether PCD body and substrate is removed from the container. Again, itis to be understood that the PCD body may be formed without using asubstrate if so desired.

The PCD body so formed may be of any appropriate thickness. Inparticular, the PCD body may have an average thickness (measured betweenthe upper surface and lower surface) of at least about 1 mm, suitably atleast about 1.5 mm, more suitably at least about 2 mm, for example inthe range of from about 1.5 mm to about 5 mm, such as 2.25 mm, 2.5 mm,2.75 mm, 3 mm, 3.25 mm, 3.5 mm or 4 mm.

PCD bodies useful for forming ultra-hard constructions as disclosedherein may include those formed at HPHT conditions, such as thosedisclosed in US 2010/0294571 A1, which is incorporated herein byreference. Such PCD bodies can be formed at higher pressures ofapproximately 5.4 GPa to 6.3 GPa (cold cell pressures), which correspondto approximately 6.2 GPa to 7.1 GPa as temperatures are increased pastthe cobalt/carbon eutectic line. In example embodiments, the pressure(at high temperature) is in the range of approximately 6.2 to 7.2 GPa.In various embodiments, the cell pressure (at high temperature) may begreater than 6.2 GPa, for example in the range of from greater than 6.2GPa to 8 GPa or from 6.3 GPa to 7.4 GPa, such as 6.25 GPa, 6.35 GPa, 6.4GPa, 6.45 GPa, 6.5 GPa, 6.6 GPa, or 6.7 GPa.

FIG. 5B schematically illustrates an example embodiment polycrystallinediamond construction 30 of the present disclosure after a second stageof formation, specifically at a stage where the solvent catalystmaterial used to initially form/sinter the diamond body and disposed inthe interstitial regions and/or attached to the surface of the bondedtogether diamond particles has been removed from the diamond body 32. Atthis stage of making the construction, the PCD body has a materialmicrostructure resembling region 22 that is illustrated in FIG. 4B,comprising the diamond matrix phase formed from a plurality of bondedtogether diamond particles 24, and interstitial regions 26 that aresubstantially free of the specific catalyzing material, e.g., cobalt,that was used during the sintering process to initially form the body ofbonded diamond particles and that remains from that sintering processused to initially form the diamond matrix phase.

As used herein, the term “removed” is used to refer to the reducedpresence of the specific material in the body, for example the reducedpresence of the catalyst material that was used to initially form thediamond body during the HPHT sintering process, and is understood tomean that a substantial portion of the material (e.g., catalyst,infiltrant, and/or filler material) no longer resides within the regionof the body. However, it is to be understood that some small traceamounts of the material may still remain in the microstructure of theregion of the PCD body within the interstitial regions and/or adhered tothe surface of the diamond particles.

Additionally, the term “substantially free,” as used herein to refer tothe portion of the remaining diamond body after the specific materialhas been removed, is understood to mean that there may still be sometrace/residual small amounts of the specific material remaining withinthe region of the body as noted above. In one or more embodiments, thebody may be treated such that more than 98 percent by weight (% w),based on the total weight of the treated region, has had the materialremoved from the interstitial regions within the treated region, inparticular at least 99% w, more in particular at least 99.5% w, samebasis, may have had the material removed from the interstitial regionswithin the treated region. At most 2 percent by weight (% w), based onthe total weight of the region of the PCD body, for example at most 1.5%w, 1% w, or 0.5% w, same basis, may remain.

For example, trace amounts of catalyst material may remain within thetreated PCD body due to the catalyst material being trapped in theregions of diamond regrowth (diamond-to-diamond bonding) and is notnecessarily removable by treatment methods such as chemical leaching.The quantity of the specific catalyst material used to form the diamondbody remaining in the material microstructure after the diamond body hasbeen subjected to treatment to remove the same can and will vary on suchfactors as the efficiency of the removal process, and the size anddensity of the diamond matrix material.

In an example embodiment, the catalyst material used to form the PCDbody may be removed therefrom by a suitable process, such as by chemicaltreatment such as by acid leaching or aqua regia bath, electrochemicallysuch as by electrolytic process, by liquid metal solubility technique,or by combinations thereof. In one or more embodiments, the catalystmaterial is removed by an acid leaching technique, such as thatdisclosed for example in U.S. Pat. No. 4,224,380, which is incorporatedherein by reference.

Accelerating techniques for removing the catalyst material may also beused, and may be used in conjunction with the leaching techniques notedabove as well as with other conventional leaching processing. Suchaccelerating techniques include elevated pressures, elevatedtemperatures and/or ultrasonic energy, and may be useful to decrease theamount of treatment time associated with achieving the same level ofcatalyst removal, thereby improving manufacturing efficiency.

In one embodiment, the leaching process may be accelerated by conductingthe same under conditions of elevated pressure that may be greater thanabout 5 bar and that may range from about 10 to 50 bar in otherembodiments. Such elevated pressure conditions may be achieved byconducting the leaching process in a pressure vessel or the like. It isto be understood that the exact pressure condition can and will vary onsuch factors as the leaching agent that is used as well as the materialsand sintering characteristics of the diamond body.

In addition to elevated pressure, elevated temperatures may also be usedfor the purpose of accelerating the leaching process. Suitabletemperature levels may be in the range of from about 90 to 350° C. inone embodiment, and up to 175 to 225° C. in another embodiment. In oneor more embodiments, elevated temperature levels may range up to 300° C.It is to be understood that the exact temperature condition can and willvary on such factors as the leaching agent that is used as well as thematerials and sintering characteristics of the diamond body. It is to beunderstood that the accelerating technique may include elevated pressurein conjunction with elevated temperature, which would involve the use ofa pressure assembly capable of producing a desired elevated temperature,e.g., by microwave heating or the like. For example, amicrowave-transparent pressure vessel may be used to implement theaccelerated leaching process. The accelerating technique may includeelevated temperature or elevated pressure, i.e., one or the other andnot a combination of the two.

Ultrasonic energy may be used as an accelerating technique that involvesproviding vibratory energy operating at frequencies beyond audiblesound, e.g., at frequencies of about 18,000 cycles per second andgreater. A converter or piezoelectronic transducer may be used to form adesired ultrasonic stack for this purpose, wherein the piezoelectriccrystals may be used to convert electrical charges to desired acousticenergy, i.e., ultrasonic energy. Boosters may be used to modify theamplitude of the mechanical vibration, and a sontotrode or horn may beused to apply the vibration energy. The use of ultrasonic energy mayproduce an 80 to 90 percent increase in leaching depth as a function oftime as compared to leaching without using ultrasonic energy, therebyproviding a desired decrease in leaching time and an improvement inmanufacturing efficiency.

Referring again to FIG. 5B, at this stage of the process any substrate34 that was used as a source of the catalyst material may be removedfrom the diamond body 32, and/or may fall away from the diamond bodyduring the process of catalyst material removal. In an exampleembodiment, it may be desired to remove the substrate from the diamondbody before treatment to facilitate the catalyst removal process, e.g.,so that all surfaces of the diamond body may be exposed for the purposeof catalyst material removal. If the source of the catalyst material wasprovided by mixing with or otherwise providing with the precursordiamond powder, then the polycrystalline construction 30 at this stageof manufacturing will not contain a substrate, i.e., it will consist ofa diamond body 32.

FIG. 5C schematically illustrates an example embodiment polycrystallineconstruction 30 prepared in accordance with the present disclosure aftera third stage of formation. Specifically, at a stage where the catalystmaterial used to initially form the diamond body has been removedtherefrom and has been replaced with a desired infiltrant material 38and filler material 36. As noted above, the infiltrant material may beselected from the group of materials including metals, ceramics, cermetsand combinations thereof. In an example embodiment, the infiltrantmaterial is a metal, a mixture of metal or an alloy of metal. In one ormore embodiments, the infiltrant material may be a metal or metal alloyselected from Group VIII of the Periodic table, such as cobalt, nickel,iron, combinations and alloys thereof. It is to be understood that thechoice of material or materials used as the infiltrant material can andwill vary depending on such factors including but not limited to theend-use application, and the type and density of the diamond grains usedto form the polycrystalline diamond matrix first phase, and themechanical properties and/or thermal characteristics desired for thepolycrystalline diamond construction.

Referring back to FIG. 4B, once the catalyst material used to initiallyform the diamond body is removed from the diamond body, the remainingmicrostructure comprises a polycrystalline matrix phase with a pluralityof interstitial voids 26 forming what is essentially a porous materialmicrostructure. This porous microstructure not only lacks mechanicalstrength, but also lacks a material constituent that is capable offorming a strong attachment bond with a substrate, e.g., in the eventthat the polycrystalline diamond construction needs to be in the form ofa compact comprising such a substrate to facilitate attachment to anend-use device.

A population of the voids or pores in the polycrystalline diamond bodymay be filled with the infiltrant material using a number of differenttechniques. Only a portion of the voids in the diamond body may befilled with the infiltrant material. In one or more embodiments, theinfiltrant material may be introduced into the diamond body byliquid-phase sintering under HPHT conditions (infiltration process orre-bonding process). In such embodiments, the infiltrant material may beprovided in the form of a sintered part or a green-state part thatcontains the infiltrant material and that is positioned adjacent one ormore surfaces of the diamond body. The assembly may be placed into acontainer that is subjected to HPHT conditions sufficient to melt theinfiltrant material within the sintered part or green-state part andcause it to infiltrate into the diamond body. In one or moreembodiments, the source of the infiltrant material may be a substratethat will be used to form a compact from the polycrystalline diamondconstruction by attachment to the diamond body during the HPHTre-bonding process.

Rather than using a pre-formed substrate as a source of the infiltrantmaterial, the diamond body may have a desired powder volume that ispositioned adjacent one or more surfaces of the diamond body to providethe infiltrant material. In an example embodiment, the desired powder isa metal material containing the infiltrant material. In an exampleembodiment, the desired powder is formed from one or more materials thatmay be sintered to provide an element that is attached to the diamondbody and that has desired properties to facilitate use of the resultingsintered polycrystalline diamond construction in a cutting and/or wearapplication, for example the powder mixture may comprise a WC—Comaterial. When subjected to HPHT conditions, the cobalt in such powdermixture melts and infiltrates into the diamond body. Instead of powder,the infiltrant material can be provided adjacent a surface of thediamond body in the form of a foil or disc or the like by chemicalplating operations, by electroplating operations or the like, where thedesired infiltrant material is deposited on the diamond body surface.

The term “filled,” as used herein to refer to the presence of theinfiltrant material and/or filler material in the voids or pores of thediamond body that resulted from removing the catalyst material used toform the diamond body therefrom, is understood to mean that asubstantial volume of such voids or pores contain the infiltrantmaterial and/or filler material. It is understood that a population ofthe voids or pores of the diamond body within a particular region mayremain substantially empty or partially filled due to non-uniform poresize, temperature gradients which may be present in the press cell orthe composition of the substrate.

Another population of the voids or pores in the polycrystalline diamondbody may be filled with the filler material using one or more of thetechniques discussed above for introducing the infiltrant material intothe PCD body. Only a portion of the voids in the diamond body may befilled with the filler material. In one or more embodiments, the fillermaterial may be introduced into the diamond body by liquid-phasesintering under HPHT conditions (infiltration process or re-bondingprocess). In an example embodiment the filler material may be providedin the form of a pre-formed body, such as a ring, foil, disc, substrateand the like, or in the form of powder, by spray coating or by otherdeposition method capable of delivering the filler material to a desiredsurface of the diamond body. In an example embodiment, where the fillermaterial is provided in the form of a pre-formed body, such body may bepositioned adjacent one or more surfaces of the diamond body (e.g.,working surfaces) after the metal catalyst material used to initiallyform the same has been removed. The amount of filler material introducedinto the PCD body may be controlled by adjusting the size and shape ofthe pre-formed body.

The filler material may be introduced into the PCD body by placing apowder material containing the filler material adjacent one or moresurfaces of the diamond body (e.g., working surfaces) after the metalcatalyst material used to initially form the same has been removed. Theamount of filler material introduced into the PCD body may be controlledby adjusting the quantity of powder material placed adjacent the PCDbody.

The filler material may be introduced into the PCD body by a pressuretechnique where the filler material may be provided in the form of aslurry or the like comprising the desired filler material and a carrier,e.g., such as a polymer or organic carrier. The slurry may then beexposed to the diamond body (e.g., working surfaces) at high pressure tocause the slurry to enter the diamond body and cause the filler materialto fill the voids therein. The PCD body may then be subjected toelevated temperature for the purpose of removing the carrier therefrom,thereby leaving the filler material disposed within the interstitialregions. The amount of filler material introduced into the PCD body maybe controlled by adjusting the quantity of slurry material placedadjacent the PCD body.

In one or more embodiments, the filler material has a much lower meltingtemperature than the infiltrant material, for example the meltingtemperature of the filler material may be at most 700° C., at most 600°C., at most 400° C., at most 350° C., or at most 300° C. In an exampleembodiment, the filler material has a melting temperature that is lessthan that of the infiltrant material, at atmospheric conditions, forexample by at least about 400° C., preferably by at least about 1,000°C., and more preferably by at least about 1,200° C.

In one or more embodiments, the filler material may be introduced intothe PCD body prior to introducing the infiltrant material since theintroduction of the filler material may take place at a temperaturesignificantly below the thermal degradation temperature of the PCD body(filling process). The conditions during such a filling process mayinclude pressures of at least at least 50 kbar, and at temperature of atleast 150° C.

The filler material may be introduced into the PCD body during the sameprocess utilized to infiltrate the PCD body with the infiltrant material(infiltrating process or re-bonding process). In this embodiment, theassembly includes the filler material positioned adjacent one or moresurfaces of the PCD body (e.g., working surfaces).

The assembly containing the filler material (whether contained withinthe pores of the PCD body or adjacent a surface of the PCD body) and theinfiltrant material is subjected to HPHT conditions sufficient to causethe infiltrant (e.g., cobalt from the substrate) to melt, infiltrateinto, and fill a population of the voids or pores in the polycrystallinediamond matrix not already filled by the filler material.

A substrate used as a source for the infiltrant material may have amaterial make up and/or performance properties that are different fromthat of a substrate used to provide the catalyst material for theinitial sintering of the diamond body. For example, the substrateselected for sintering the diamond body may comprise a material make upthat facilitates diamond bonding, but that may have poor erosionresistance and as a result not be well suited for an end-use applicationin a drill bit. In this case, the substrate selected at this stage forproviding the source of the infiltrant material may be selected frommaterials different from that of the sintering substrate, e.g., frommaterials capable of providing improved down hole properties such aserosion resistance when attached to a drill bit. Accordingly, it is tobe understood that the substrate material selected as the infiltrantmaterial source may be different from the substrate material used toinitially sinter the diamond body.

In an example embodiment, wherein a PCD material is treated to removethe solvent metal catalyst material, e.g., cobalt, used to initiallyform the same therefrom, the resulting diamond body is subjected to aHPHT re-bonding process for a period of approximately 100 seconds at atemperature sufficient to meet the melting temperature of the infiltrantmaterial, which is cobalt. The source of the cobalt infiltrant materialis a WC—Co substrate that is positioned adjacent a desired surfaceportion of the diamond body prior to HPHT re-bonding processing. Afiller material, e.g., tin (Sn), in the form of a foil is placedadjacent the upper surface of the treated PCD body. FIG. 6A illustratesa partial cross-sectional view (the surrounding can has been omitted forpurposes of clarity) of an assembly prior to the re-bonding process.Substrate 634 is placed adjacent a lower surface 665 of the treated PCDbody 610, and a pre-formed foil of the filler material 635 is placedadjacent an upper surface 664 of the treated PCD body 610.

The assembly is placed in an HPHT device, and the HPHT process iscontrolled to bring the contents to the melting temperature of cobalt(about 1,350° C., at a pressure of about 3,400 to 7,000 MPa) to enablethe cobalt to infiltrate into and fill a population of pores or voids inthe diamond body adjacent the substrate, and to enable the fillermaterial to infiltrate into and fill another population of pores ofvoids in the diamond body adjacent the foil.

Referring to FIG. 1, the HPHT process is controlled to subject thesintered diamond body to different conditions identified in FIG. 1 asRegions 1, 2 and 3. Initially, the diamond body is subjected to atemperature sufficient to melt the filler material. In an exampleembodiment, this temperature is less than about 700° C., and isunderstood to vary depending on the particular filler material that isselected. The pressure within Region 1 may be above or below theBerman/Simon diamond-graphite equilibrium line, depending on the amountof pressure useful for causing the melted filler material to enter thediamond body. In an example embodiment, the filler material isinfiltrated into the diamond body at a pressure of less than about 3GPa. Thus, the pressure for Region 1 may be above or below thediamond-graphite equilibrium line depending on such factors as theinterstitial pore sizes, and the type of filler material that isselected. In an example, the pressure in Region 1 may be about 1 GPaabove the diamond-graphite equilibrium line, to ensure that the fillermaterial infiltrates into the diamond body. Thus, within Region 1 of theHPHT process, the filler material melts and is infiltrated into thediamond body to form a filler region as described above. In an exampleembodiment within Region 1, when the filler material melts and theprocess is at an appropriate pressure, the filler material infiltratesand sweeps into the diamond body within a very short time, e.g., withina fraction of a second. The rate of infiltration may be controlleddepending on how aggressive the heat ramp is set within Region 1. Insuch example embodiment, the filler infiltration into the diamond bodystabilizes over a period of from about 30 to 600 seconds.

Subsequently, the HPHT process is controlled to progress from Region 1to Region 2 by increasing the temperature and pressure exerted on thediamond body now containing the filler region. In an example embodiment,the temperature in Region 2 is increased from about 700° C. to atemperature that is below the melting point of the infiltrant material,e.g., for cobalt, less than about 1,350° C. In Region 2, the pressureduring the HPHT process is also increased for the purpose oftransitioning from Region 1 to cause the infiltrant material to bemelted and infiltrate into the diamond body within Region 3.

In an example embodiment, the pressure in Region 2 may be above or below(as illustrated in Region 2 a) the diamond-graphite equilibrium line,depending on the particular pressure exerted in Region 1. In an exampleembodiment, the pressure in Region 2 is about 1 GPa above thediamond-graphite equilibrium line to stay within the diamond stableregion during a simultaneous pressure and temperature ramp and providesome operating window to account for cell to cell variation. However,when using filler materials that do not require pressurization into thediamond stable region (above the diamond-graphite equilibrium line) forinfiltration in Region 1, it may be advantageous to simply ramp quicklythrough at least a portion of Region 2 a below the diamond-graphiteequilibrium line on the way to Region 3 to minimize any extremetransition.

Within Region 2, the diamond body, comprising the filler region, issubjected to increasing pressure and temperature as it approaches Region3. A feature of the controlled HPHT process and use of the fillermaterial as disclosed herein, is that the presence of the so-formeddiamond body filler region operates to keep the diamond body in anisostatic condition within in the diamond stable region as the pressureis increased (in Regions 2 and 3), thereby minimizing the possibility ofthe diamond bonds being broken and/or the diamond structure beingdamaged with increasing pressure.

As the HPHT process is continued, it reaches Region 3 wherein thetemperature is increased to an amount sufficient to melt the infiltrantmaterial. The pressure in Region 3 is controlled to be at or above theBerman/Simon diamond-graphite equilibrium line to keep the diamond bodyin the diamond stable region or state. In Region 3, the meltedinfiltrant material infiltrates under pressure into the diamond bodyforming an infiltrant region to fill the interstitial regions or poreswithin such region. In Region 3, the filler region operates togetherwith the infiltrant region to keep the entire diamond body in anisostatic condition within the diamond stable region or state, therebyminimizing or eliminating the possibility of the diamond body sustainingstructural damage during the HPHT process, which damage could otherwisewell occur due to the presence of a sufficient amount of unfilledinterstitial regions or pores. During the HPHT re-bonding process, thesubstrate containing the infiltrant material, e.g., cobalt, is attachedto the diamond body to thereby form a polycrystalline diamond compactconstruction. The cobalt from the substrate is the sole source ofinfiltrant material.

In an example embodiment, it is desired that the diamond body comprisesa filler region and an infiltrant region that together operate to reducethe population of unfilled interstitial regions within the diamond bodyduring HPHT conditions when in Region 3 to less than about 2 percent tomaintain the diamond body in a desired diamond-stable state and protectit against undesired damage to the diamond structure. In an exampleembodiment, the population of unfilled interstitial regions within thediamond body during HPHT processing in Region 3 may be from about 0 to 2percent, preferably be from about 0 to 1 percent, and most preferably be0, or 100 percent of the interstitial regions within the diamond bodyare filled (with either the filler material and/or the infiltrantmaterial) when the diamond body is subjected to the HPHT processingconditions of Region 3.

FIG. 6B illustrates a cross-sectional view of a re-bonded PCD compactconstruction after infiltration of the infiltrant and filler materials.The infiltrated PCD body 611 contains a filler region 633 andinfiltrated region 622. The infiltrated region 622 is located adjacentthe substrate, extending a depth into the body from the substrate, andthe filler region 633 extends a depth into the body from a surfaceopposite the substrate. The major portion of the filler region 633 hasinterstitial regions/pores filled with filler material consisting oftin. The major portion of the infiltrant region 622 has interstitialregions/pores filled with infiltrant material. While the interfacebetween the region 633 and 622 has been illustrated as being straight orplanar, it is to be understood that the interface configuration can andwill vary depending on such factors as the thickness, size and/or shapeof the filler material source, and/or the heating balance in the cell.In some embodiments the interface can be nonplanar in cross section,e.g., concave or convex.

While the PCD compact construction illustrated in FIG. 6B depicts thediamond body 611 bonded directly to the substrate 634, it is to beunderstood that PCD constructions as disclosed herein may include one ormore transition layer interposed between the diamond body and thesubstrate. In an example embodiment, such transition layer may be usedto provide a transition in one or more properties between the diamondbody and substrate. In an example embodiment, the transition layer maybe used to provide a transition in the thermal expansion characteristicsbetween the diamond body and the substrate, wherein such transitionlayer may have a diamond content that is less than that of the diamondbody and preferably within between about 80 to 95 wt %.

In an example embodiment, subsequent to the HPHT re-bonding process, thePCD construction illustrated in FIG. 6B is subsequently treated toremove the filler material therefrom. If desired, all or a portion ofthe infiltrant material can also be removed during the same or differenttreatment. In an example embodiment, the filler material is removed fromthe filler region, and infiltrant material is leached from a portion ofthe infiltrant region to thereby form a thermally stable regionadjacent: 1) the entire upper surface; 2) the entire cutting edge; and3) a portion of the length of the side surface of the PCD body(including the entire circumferential distance of the side surface).

As illustrated in FIG. 6C, a cross-sectional view of the PCD compactshows the thermally stable region 644 (that is substantially free of thefiller and infiltrant materials) as extending a depth from the top andside surfaces, and the remaining infiltrated region 655 extending to thesubstrate 634. The particular embodiment illustrated in FIG. 6C showsthermal region having a depth, as measured from the diamond body topsurface, that is greater near the circumferential edge than near themiddle, the depth decreases moving radially inwardly from the sidesurfaces towards the center. This is understood as being but oneembodiment illustrating a configuration of the thermally stable regionand that configurations other than that disclosed and illustrated areintended to be within the scope of the PCD constructions as disclosedherein.

It is advantageous to utilize a low-melting temperature filler materialas described herein because such material readily infiltrates and sweepsthrough and into the pores of the treated PCD body at temperatures andpressures, i.e., during an HPHT process, that are much lower than thosenecessary for introducing the infiltrant into the PCD body. Thus, uponsubsequent infiltration of the infiltrant, which occurs at highertemperatures and pressures during the HPHT process, the interstitialregions or pores of the treated PCD body are sufficiently filled witheither the filler material or the infiltrant to ensure that the treatedPCD body remain in the diamond stable region, i.e., above theBerman/Simon diamond-graphite equilibrium line, during infiltration ofthe infiltrant. This operates to protect and prevent regions of the PCDbody from being damaged or otherwise converted to from diamond tographite, essentially providing a PDC body capable of maintaining anisostatic condition during HPHT processing to resist structural failuresotherwise known to occur with conventional PCD bodies subjected toconventional HPHT processes.

Additionally, the filler materials selected are those that can moreeasily migrate and infiltrate into the small pores of the treated PCDbody then conventional infiltrants, thereby permitting a deeper level ofinfiltration into the PCD body than otherwise possible usingconventional infiltrants. Further, such filler materials can also bemore easily removed from the small pores of the re-infiltrated PCD body,thereby allowing for the creation of a deeper thermally stable regionwithin the PCD body once removed, than practically permissible usingconventional infiltrants materials.

Techniques useful for removing infiltrant or filler material from thediamond body include the same ones described above for removing thecatalyst material used to initially form the diamond body, e.g., such asby acid leaching or the like. In an example embodiment, it is desiredthat the process of removing the filler material and optionally theinfiltrant material be controlled so that the material be removed from atargeted region of the diamond body extending a determined depth fromone or more diamond body surfaces. These surfaces may include workingand/or nonworking surfaces of the diamond body.

In one or more embodiments, the filler material and optionally theinfiltrant material may be removed from the diamond body to any suitabledepth. In one or more embodiments, the filler material and optionallythe infiltrant material may be removed from the diamond body to a depthof at most about 2 mm from the desired surface or surfaces. In one ormore embodiments, the filler material and optionally the infiltrantmaterial may be removed from the diamond body to a depth of at leastabout 0.01 mm from the desired surface or surfaces. For example, thefiller material and optionally the infiltrant material may be removedfrom the diamond body to a depth in the range of from about 0.01 mm toabout 2 mm from the desired surface or surfaces, in particular fromabout 0.05 mm to about 1.5 mm or from about 0.1 mm to about 1 mm, suchas 0.75 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm,0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9mm or 0.95 mm. Suitably, a depth of at least about 0.3 mm may be used inone or more embodiments. Ultimately, the specific depth of the regionformed in the diamond body by removing the filler material andoptionally the infiltrant material will vary depending on the thicknessof the PCD body and the particular end-use application.

In the embodiments where a portion of the filler material is removedfrom the PCD body, the filler material may be any material capable offilling a population of pores within the treated PCD body and which hasa melting temperature that is lower than the infiltrant material.Suitably, such filler materials may be selected from aluminum, gallium,copper, zinc, silver, indium, thallium, tin, lead, bismuth, alloys andmixtures thereof. In an example embodiment, the filler material may beselected from aluminum, gallium, indium, thallium, tin, lead, bismuth,alloys and mixtures thereof. In an example embodiment, the fillermaterial may be selected from tin, lead, bismuth, alloys and mixturesthereof. In an example embodiment, the filler material may be selectedfrom tin, bismuth, alloys and mixtures thereof. In an exampleembodiment, the filler material may consist of tin, bismuth and alloysthereof. In an example embodiment, the filler material may consist oftin and alloys thereof. In an example, the filler material may comprise95-99% pure tin.

In the embodiments where the filler material is not removed from the PCDbody, the filler material has a melting temperature that is lower thanthe infiltrant material and may be selected from aluminum, gallium,zinc, indium, thallium, tin, lead, bismuth, alloys and mixtures thereof.In an example embodiment, the filler material may be selected fromaluminum, gallium, indium, thallium, tin, lead, bismuth, alloys andmixtures thereof. In an example embodiment, the filler material may beselected from tin, lead, bismuth, alloys and mixtures thereof. In anexample embodiment, the filler material may be selected from tin,bismuth, alloys and mixtures thereof. In an example embodiment, thefiller material may consist of tin, bismuth, and alloys thereof. In anexample embodiment, the filler material may consist of tin and alloysthereof.

In an example embodiment, the substrate used to form the polycrystallinediamond compact construction is formed from a cermet material, such asthat conventionally used to form a PCD compact. In an example, when thesubstrate is used as the source of the infiltrant material, thesubstrate may be formed from a cermet, such as a tungsten carbide (WC),further comprising a binder material that is the infiltrant materialused to fill a population of the pores within the diamond body. Suitablebinder materials include Group VIII metals of the Periodic table oralloys thereof, and/or Group IB metals of the Periodic table or alloysthereof, and/or other metallic materials having a melting temperaturethat is greater than the filler material.

In addition to the materials disclosed above, the filler material can beselected from salts, e.g., metal salts, and carbonates. Examples includealkali carbonates, alkaline earth carbonates, fluorides, chlorides,bromides, sulfides and combinations thereof, which alone or whencombined have melting points below that of the infiltrant material,e.g., cobalt, under HPHT conditions. Examples include Na₂CO₃, K₂CO₃,Na₂CO₃+K₂CO₃, MgCO₃, CaCO₃, LiCl, NaCl, KCl, Na₂CO₃-graphite, NaCl—KCl,LiCl—NaCl—KCl, and combinations and mixtures thereof. It is to beunderstood that the examples provided herein are only representative ofthe different types of metal salts, carbonates, fluorides, chlorides,bromides, sulfides and combinations thereof that can be used to formfiller materials as disclosed herein.

Although a substrate may be attached to the diamond body during theinfiltrant material introduction, it is also understood that thesubstrate may be attached to the diamond body after the desiredinfiltrant material has been introduced. In such case, the infiltrantmaterial may be introduced into the diamond body by a HPHT process thatdoes not use the substrate material as a source, and the desiredsubstrate may be attached to the diamond body by a separate HPHT processor other method, such as by brazing, welding or the like. The substratemay be attached to the diamond body before or after the filler materialand optionally infiltrant material have been removed therefrom.

If desired, an intermediate or transition material may be interposedbetween the substrate and the diamond body. The intermediate materialmay be formed from those materials that are capable of forming asuitable attachment bond between both the diamond body and thesubstrate. Suitable intermediate materials may include cermet materialscomprising a Group VIII metal such as WC—Co, WC—Co alloy, or the like.The intermediate material may be provided as a powder or a partiallysintered pre-form. The intermediate material may additionally includediamond particles forming a transition layer between the PCD body andthe substrate.

Although the interface between the diamond body and the substrateillustrated in FIG. 6C is shown as having a planar geometry, it isunderstood that this interface may also have a nonplanar geometry, e.g.,having a convex configuration, a concave configuration, or having one ormore surface features that project from one or both of the diamond bodyand substrate. Such a nonplanar interface may be desired for the purposeof enhancing the surface area of contact between the attached diamondbody and substrate, and/or for the purpose of enhancing heat transfertherebetween, and/or for the purpose of reducing the degree of residualstress imposed on the diamond body.

Further, polycrystalline diamond constructions of the present disclosuremay comprise a diamond body having properties of diamond density and/ordiamond grain size that may change as a function of position within thediamond body. For example, the diamond body may have a diamond densityand/or a diamond grain size that changes in a gradient or step-wisefashion moving away from a working surface of the diamond body. Further,rather than being formed as a single mass, the diamond body used informing polycrystalline diamond constructions as disclosed herein can beprovided in the form of a composite construction formed from a number ofdiamond bodies that have been combined together, wherein each such bodycan have the same or different properties such as diamond grain size,diamond density, or the like

Polycrystalline diamond constructions the various embodiments of thepresent disclosure display marked improvements in thermal stability andthus service life when compared to conventional PCD constructions.Polycrystalline diamond constructions of the present disclosure may beused to form wear and/or cutting elements in a number of differentapplications such as the automotive industry, the oil and gas industry,the aerospace industry, the nuclear industry, and the transportationindustry to name a few. Polycrystalline diamond constructions of thepresent disclosure are well suited for use as wear and/or cuttingelements that are used in the oil and gas industry in such applicationas on drill bits used for drilling subterranean formations.

FIG. 7 illustrates an embodiment of a polycrystalline diamond compactconstruction as disclosed here provided in the form of an insert 70 usedin a wear or cutting application in a roller cone drill bit orpercussion or hammer drill bit used for subterranean drilling. Forexample, such inserts 70 can be formed from blanks comprising asubstrate 72 formed from one or more of the substrate materials 73disclosed above, and a diamond body 74 having a working surface 76comprising a material microstructure prepared in accordance with one ormore embodiments of the present disclosure. The blanks are pressed ormachined to the desired shape of a roller cone rock bit insert.

Although the insert in FIG. 7 is illustrated having a generallycylindrical configuration with a rounded or radiused working surface, itis to be understood that inserts formed from polycrystallineconstructions of the present disclosure configured other than asillustrated and such alternative configurations are understood to bewithin the scope of the present disclosure.

FIG. 8 illustrates a rotary or roller cone drill bit in the form of arock bit 78 comprising a number of the wear or cutting inserts 70disclosed above and illustrated in FIG. 7. The rock bit 78 comprises abody 80 having three legs 82, and a roller cutter cone 84 mounted on alower end of each leg. The inserts 70 may be fabricated according to themethod described above. The inserts 70 are provided in the surfaces ofeach cutter cone 84 for bearing on a rock formation being drilled.

FIG. 9 illustrates the inserts 70 described above as used with apercussion or hammer bit 86. The hammer bit comprises a hollow steelbody 88 having a threaded pin 90 on an end of the body for assemblingthe bit onto a drill string (not shown) for drilling oil wells and thelike. A plurality of the inserts 70 is provided in the surface of a head92 of the body 88 for bearing on the subterranean formation beingdrilled.

FIG. 10 illustrates a polycrystalline construction compact of thepresent disclosure embodied in the form of a shear cutter 94 used, forexample, with a drag bit for drilling subterranean formations. The shearcutter 94 comprises a diamond body 96, prepared in accordance with oneor more embodiments of the present disclosure. The body is attached to acutter substrate 98. The PCD body 96 includes a working or cuttingsurface 100.

Although the shear cutter in FIG. 10 is illustrated having a generallycylindrical configuration with a flat working surface that is disposedperpendicular to a longitudinal axis running through the shear cutter,it is to be understood that shear cutters formed from polycrystallinediamond constructions of the present disclosure may be configured otherthan as illustrated and such alternative configurations are understoodto be within the scope of the present disclosure.

FIG. 11 illustrates a drag bit 102 comprising a plurality of the shearcutters 94 described above and illustrated in FIG. 10. The shear cuttersare each attached to blades 104 that each extend from a head 106 of thedrag bit for cutting against the subterranean formation being drilled.

One of ordinary skill in the art should appreciate after learning theteachings of the present disclosure that various other tools may use thecutting elements of the present disclosure. Such tools may includereamers, stabilizers, hole openers, down hole tool sleeves (which may bewelded to a bit).

Other modifications and variations of polycrystalline diamond bodies,constructions, compacts, and methods of forming the same according tothe principles of the present disclosure will be apparent to thoseskilled in the art. For example in the present disclosure, embodimentsmay refer to diamond or polycrystalline diamond; however, it is intendedsuch embodiments may also include ultra-hard materials generally. Forexample, the cutting edge may be depicted as having a sharp edge betweenthe top surface and side surface of the PCD body; however, such cuttingedge may also be a beveled cutting edge having a bevel angle from 20 to80 degrees. For example, two or more filler materials may be used informing the polycrystalline ultra-hard construction of the presentdisclosure.

While polycrystalline ultra-hard constructions and methods of making thesame have has been described with respect to a limited number ofembodiments, those skilled in the art having benefit of this disclosure,will appreciate that other embodiments can be devised which do notdepart from the scope of the polycrystalline ultra-hard constructionsand methods of making the same as disclosed herein. Accordingly, thescope of polycrystalline ultra-hard constructions and methods of makingthe same as disclosed herein should be limited only by the attachedclaims.

What is claimed is:
 1. A method for making an ultra-hard polycrystallineconstruction comprising: subjecting a sintered ultra-hard body that issubstantially free of a catalyst material used to initially sinter theultra-hard body at high pressure/high temperature conditions to afurther high pressure/high temperature process to introduce aninfiltrant material, wherein the sintered ultra-hard body comprises amatrix phase of directly bonded together ultra-hard particles, and aplurality of substantially empty interstitial regions disposed withinthe matrix, wherein the further high pressure/high temperature processcomprises: melting and infiltrating a filler material into the sinteredultra-hard body to form a filler region having interstitial regionsfilled with the filler material, the filler region extending a partialdepth into the sintered ultra-hard body and being formed at atemperature below the melting temperature of an infiltrant material andat a pressure below about 3 GPa; and melting and infiltrating theinfiltrant material into the sintered ultra-hard body to form aninfiltrant region, wherein melting and infiltrating the infiltrantmaterial occurs at a temperature and pressure greater than that used toform the filler region, and wherein the infiltrant region extends apartial depth into the sintered ultra-hard body.
 2. The method asrecited in claim 1, wherein the filler material has a meltingtemperature of less than about 1,000° C.
 3. The method as recited inclaim 1, wherein after melting and infiltrating the infiltrant material,the sintered ultra-hard body consists of the filler region andinfiltrant region.
 4. The method as recited in claim 1, wherein duringmelting and infiltrating the infiltrant material, a sufficientpopulation of the interstitial regions within the sintered ultra-hardbody are filled with either the filler material or the infiltrantmaterial such that the sintered ultra-hard body remains above theBerman/Simon diamond-graphite equilibrium line.
 5. The method as recitedin claim 1, wherein after melting and infiltrating the infiltrantmaterial less than about 2 percent of the population of the interstitialregions within the sintered ultra-hard body are empty.
 6. The method asrecited in claim 1, wherein after melting and infiltrating theinfiltrant material about 0 to 2 percent of the population of theinterstitial regions within the sintered ultra-hard body are empty. 7.The method as recited in claim 6, wherein after melting and infiltratingthe infiltrant material about 0 to 1 percent of the population of theinterstitial regions within the sintered ultra-hard body are empty. 8.The method as recited in claim 6, wherein after melting and infiltratingthe infiltrant material essentially 100 percent of the interstitialregions are filled.
 9. The method as recited in claim 1, furthercomprising attaching a substrate to the ultra-hard body.
 10. The methodas recited in claim 9, wherein the substrate is attached to the bodyadjacent the body infiltrant region.
 11. The method as recited in claim1, wherein the filler material is selected from the group consisting ofaluminum, gallium, copper, zinc, silver, indium, thallium, tin, lead,bismuth, alloys, metal salts, and mixtures thereof.
 12. The method asrecited in claim 1, wherein the filler material is selected from thegroup consisting of metal salts, carbonates, fluorides, chlorides,bromides, sulfides and combinations thereof.
 13. The method as recitedin claim 11, wherein the filler material is an alloy which is a eutecticalloy.
 14. The method as recited in claim 1, wherein the filler materialcomprises tin or bismuth.
 15. The method as recited in claim 1, whereinthe melting temperature of the filler material is less than about 700°C.
 16. The method as recited in claim 1, wherein the melting temperatureof the filler material is less than about 300° C.
 17. The method asrecited in claim 1, further comprising, after melting and infiltratingthe infiltrant material, treating the ultra-hard body to remove thefiller material from the filler region to provide a thermally stableregion.
 18. The method as recited in claim 17, wherein the thermallystable region contains less than about 12 percent by weight fillermaterial, based on the total weight of the ultra-hard body.
 19. Themethod as recited in claim 17, wherein the thermally stable regioncontains less than about 2 percent by weight filler material, based onthe total weight of the ultra-hard body.
 20. The method as recited inclaim 1, wherein substantially all the ultra-hard particles in theultra-hard body are directly bonded to one another.
 21. The method asrecited in claim 1, further comprising placing the filler materialadjacent a working surface of the ultra-hard body before melting andintroducing the filler material.
 22. The method as recited in claim 9,wherein the infiltrant material is provided from the substrate.
 23. Themethod as recited in claim 1, wherein the infiltrant material comprisesone or more Group VIII elements of the Periodic table, alloys, andmixtures thereof.
 24. The method as recited in claim 1, wherein theinfiltrant material and the catalyst material are different.
 25. Themethod as recited in claim 24, wherein the infiltrant material and thecatalyst material both comprise cobalt.
 26. The method as recited inclaim 1, wherein the ultra-hard material is diamond, and the matrixphase is intercrystalline bonded together diamond crystals.
 27. Themethod as recited in claim 1, wherein during melting and infiltratingthe infiltrant material, a substrate is used as a source to introducethe infiltrant material, wherein the substrate is different from asubstrate used to introduce the catalyst material initially used tosinter the ultra-hard body.
 28. The method as recited in claim 27,wherein the substrate used as a source for the infiltrant material has amaterial makeup that is different from the substrate used to introducethe catalyst material.
 29. The method as recited in claim 17, whereinthe thermally stable region extends a depth of at least about 0.5 mmfrom a surface of the ultra-hard body including one or both of a top andside surface.
 30. The method as recited in claim 17, further comprisingtreating the ultra-hard body to remove a portion of the infiltrantmaterial so that the thermally stable region includes a portion of theinfiltrant region.
 31. A polycrystalline ultra-hard constructiondisposed in a high pressure/high temperature device, the constructioncomprising: a sintered ultra-hard body having a material microstructurecomprising a matrix phase of directly bonded together ultra-hardparticles formed at high pressure/high temperature conditions in thepresence of a catalyst material, the ultra-hard body having a surfaceand including interstitial regions disposed within the matrix phase,wherein the interstitial regions within the ultra-hard body aresubstantially free of the catalyst material; wherein the ultra-hard bodyis at a temperature and pressure sufficient to melt and infiltrate afiller material into the ultra-hard body to form a filler region,wherein the pressure is less than about 3 GPa, the interstitial regionswithin the filler region comprising the filler material, and wherein theremaining interstitial regions in the ultra-hard body are substantiallyfree of the filler material and the catalyst material; and an infiltrantmaterial positioned adjacent the ultra-hard body, wherein the infiltrantmaterial is in a solid state at the pressure and temperature.
 32. Theconstruction as recited in claim 31, wherein the filler material isselected from the group consisting of aluminum, gallium, zinc, indium,thallium, tin, lead, bismuth, alloys, metal salts, and mixtures thereof,wherein the filler region extends into the ultra-hard body a depth fromthe surface.
 33. The construction as recited in claim 31, wherein thetemperature is less than about 700° C.
 34. The construction as recitedin claim 31, wherein the pressure is less than about 2.5 GPa.
 35. Apolycrystalline diamond construction comprising an ultra-hard bodyhaving a thermally stable region and an infiltrant region that is formedby the process comprising; subjecting a sintered ultra-hard body to ahigh pressure/high temperature process, the sintered ultra-hard bodycomprising a matrix phase of intercrystalline bonded together diamondcrystals that extends throughout the body, the body including aplurality of interstitial regions disposed within the matrix phase,wherein the interstitial regions are substantially free of a catalystmaterial that was used to initially form the sintered ultra-hard body,the high pressure/high temperature process comprises; melting andinfiltrating a filler material at a first temperature and first pressurecondition to form a filler region in the ultra-hard body, wherein theinterstitial regions within the filler region comprise the fillermaterial, the first pressure condition being less than about 3 GPa, thefiller region extending into the ultra-hard body a partial depth from anultra-hard body first surface; melting and infiltrating an infiltrantmaterial at a second temperature and second pressure condition to forman infiltrant region in the ultra-hard body, wherein the interstitialregions within the infiltrant region comprise the infiltrant material,the second temperature condition being greater than the firsttemperature condition, and the second pressure condition being greaterthan the first pressure condition, wherein the ultra-hard bodycomprising the filler region and the infiltrant region at the secondtemperature and second pressure condition is in a diamond stable stateabove the Berman/Simon diamond-graphite equilibrium line; and treatingthe ultra-hard body comprising the filler region and infiltrant regionto remove the filler material from a population of the interstitialregions within the filler region to form a thermally-stable region thatis substantially free of the filler material, and that extends a depthfrom the ultra-hard body surface.
 36. The construction as recited inclaim 35, wherein the ultra-hard body comprises the infiltrant regionand the thermally stable region, and is substantially free of the fillerregion.
 37. The construction as recited in claim 36, wherein thethermally stable region extends a depth into the infiltrant region,wherein the interstitial regions within the thermally stable region aresubstantially free of the infiltrant material.
 38. The construction asrecited in claim 35, wherein the filler material is an alloy which is aeutectic alloy.
 39. The construction as recited in claim 35, wherein thefiller material comprises tin or bismuth.
 40. The construction asrecited in claim 35, wherein the melting temperature of the fillermaterial is less than about 700° C.
 41. The construction as recited inclaim 35, wherein the melting temperature of the filler material lessthan about 300° C.
 42. The construction as recited in claim 35, whereinthe infiltrant material comprises one or more Group VIII elements of thePeriodic Table, alloys, and mixtures thereof.
 43. The construction asrecited in claim 35, wherein the infiltrant material and the catalystmaterial are different.
 44. The construction as recited in claim 43,wherein the infiltrant material and the catalyst material both comprisecobalt.
 45. The construction as recited in claim 35, wherein the surfacecomprises a working surface including a top surface and a side surfaceof the ultra-hard body, and wherein the thermally stable region extendsa depth of at least about 0.5 mm from both the top and side surfaces.46. The construction as recited in claim 45, further comprising abeveled cutting edge interposed between the top and side surfaces, andwherein the thermally stable region extends a depth therefrom.
 47. Theconstruction as recited in claim 35, further comprising a substrateattached to the ultra-hard body adjacent the infiltrant region.
 48. Theconstruction as recited in claim 35, wherein the ultra-hard body has athickness of greater than about 1 mm.
 49. A method for making anultra-hard polycrystalline construction comprising: subjecting aplurality of ultra-hard particles to a high pressure/high temperaturecondition in the presence of a catalyst material to form apolycrystalline ultra-hard material comprising a matrix phase ofdirectly bonded together ultra-hard particles, and a plurality ofinterstitial regions disposed within the matrix phase which include thecatalyst material; treating the polycrystalline ultra-hard material toremove the catalyst material therefrom to form an ultra-hard body thatis substantially free of the catalyst material used to initially formthe polycrystalline ultra-hard material; introducing a filler material,wherein the filler material fills a population of the plurality ofinterstitial regions of the ultra-hard body in a first region extendinga depth from a surface of the ultra-hard body, wherein the first regionis formed at a first temperature and at a pressure of less than about 3GPa; introducing an infiltrant material into the ultra-hard bodycomprising the first region at a temperature greater than the firsttemperature, wherein the infiltrant material fills a population of theplurality of interstitial regions of the ultra-hard body in a secondregion, wherein the second region is formed while the ultra-hard body isin a diamond stable state above the Berman/Simon diamond-graphiteequilibrium line; and attaching a substrate to the ultra-hard body. 50.The method of claim 49, further, comprising treating the ultra-hard bodyto remove at least a portion of the filler material therefrom to form athermally stable region that is substantially free of the fillermaterial.
 51. The method of claim 50, further comprising treating theultra-hard body to remove at least a portion of the infiltrant materialtherefrom to form the thermally stable region that is substantially freeof the infiltrant material.
 52. The method as recited in claim 49,wherein the thermally stable region extends a depth of less than about0.2 mm from the surface.
 53. The method as recited in claim 49, whereinthe filler material is selected from the group consisting of aluminum,gallium, zinc, indium, thallium, tin, lead, bismuth, carbonates,sulfates, hydroxides, chlorides, alloys, metal salts, and mixturesthereof.